Stage unit and its making method, and exposure apparatus and its making method

ABSTRACT

By applying a force to cancel a reaction acting on a stator due to driving of a mover to the stator by an electromagnetic interaction generated between reaction canceling magnetic pole units and armature coils, and by having a magnetic pole unit, which constitutes the mover, composed by combining magnets having such magnetization-directions that their magnetic flux are toward the stator and magnets having magnetization-directions crossing the aforementioned magnetization-directions without using yoke material for the mover to be light weight, the vibration of the stator can be prevented even upon the high speed drive of the mover. Therefore, a highly precise positioning control can be performed while moving a placed sample at high speed.

TECHNICAL FIELD

The present invention relates to a stage unit and its making method, andan exposure apparatus and its making method, and, more specifically, astage unit which controls the position of a sample placed on itself andits making method, and an exposure apparatus which is equipped with thestage unit and transfers a predetermined pattern onto a wafer, and itsmaking method.

BACKGROUND ART

In a lithography process for making a semiconductor device, liquidcrystal display device, or the like, an exposure apparatus has beenused. In such an exposure apparatus, patterns formed on a mask orreticle (to be generically referred to as a “reticle” hereinafter) aretransferred through a projection optical system onto a substrate such asa wafer or glass plate (to be referred to as a “substrate” or “wafer”hereinafter, as needed) coated with a resist, etc. As apparatuses ofthis type, a static exposure type projection exposure apparatus, e.g., aso-called stepper, and a scanning exposure type projection exposureapparatus, e.g., a so-called scanning stepper are mainly used. Such anexposure apparatus is equipped with a stage unit, which is movable intwo-dimensional directions while holding a wafer, to transfer a patternformed on a reticle onto a plurality of shot areas on the wafer in turn.

In such a stage unit, the wafer is held on a wafer holder by vacuumchucking, etc. and fixed on a wafer table (movable body) to set theposition of the wafer to a exposure position with high accuracy. Suchwafer tables have been driven along a mechanical guide surface by adriving unit mechanically in contact with the wafer table and movable.Therefore, stage units have been equipped with X-stage to drive thewafer table in X direction and Y-stage to drive the wafer table togetherwith X-stage in Y direction to move the wafer table on the X-Y plane.

Meanwhile, the development of a stage unit which controls the positionof a wafer with high accuracy without being affected by the mechanicalaccuracy, etc. of a guide surface and performs positioning of the waferby supporting a flat-plate-like shaped and movable body, on which thewafer is placed above a supporting member, by levitation and driving themovable body in a non-contacting manner to avoid mechanical friction andprolong the life of the stage is in progress. As such stage units, avariable magnetic reluctance driving method in which a linear pulsemotor, as in a Sawyer motor, using the variable magnetic reluctancedriving method is so structured that two axes are combined with eachother, and a stage unit using a planar motor as a driving unit (driver)employing a Lorentz (electromagnetic) force method disclosed in, forexample, Japanese Patent Laid-Open No. 58-175020 and U.S. Pat. No.5,196,745 have been suggested.

Recently, wafers on which patterns are transferred by an exposureapparatus are being enlarged. Along with the enlargement of wafers, awafer table as a table on which a wafer is placed is also enlarged andnecessarily the weight of the wafer table is increased. Therefore it isnecessary to drive the wafer table by a large force to move the wafer athigh speed for the improvement of the through-put of the exposureapparatus.

Incidentally on driving the wafer table, the wafer table and a mover aremoved together as one entity against a stator using a driving unitcomprising the mover and the stator and on this occasion, a reaction tothe force applied to the mover is induced in the stator. As aconsequence, a vibration occurs and is transmitted to other members whenthe mover is mechanically connected with other members of the exposureapparatus, and then inflicts a bad effect on exposure accuracy. Forexample, when the mover is mechanically connected with a supportingmember with respect to a projection optical system of the exposureapparatus, the projection optical system will vibrate and cause thedegradation of the exposure accuracy.

Such a bad effect to the exposure accuracy generally becomes severeralong with the increase of drive force of the mover. Therefore alongwith the enlargement of wafers, the mover is driven by a large force tomove the wafer at high speed for the improvement of the through-put andthe exposure accuracy will be degraded remarkably. That is, along withthe enlargement of wafers it is getting difficult to improve both thethrough-put and the exposure accuracy.

The present invention has been made in view of the condition above. Afirst object of the present invention is to provide a stage unit thatcan move a placed sample at high speed and perform accurate positioning.

Also, a second object of the present invention is to provide an exposureapparatus that can improve both the through-put and the exposureaccuracy by high speed movement of a substrate and highly accuratepositioning.

DISCLOSURE OF INVENTION

From a first aspect, the present invention is a stage unit that isequipped with a driving unit including a mover and a stator; and areaction canceling mechanism to apply to the stator a force canceling areaction acting on the stator by electromagnetic interaction. This stageunit is referred to as a “first stage unit of the present invention”hereafter.

According to the present invention, the reaction canceling mechanismgenerates a force to cancel the reaction acting on the stator by usingelectromagnetic interaction excellent in controllability and linearityand applies it to the stator, thereby accurately canceling the reactionacting on the stator. Accordingly, even with the increase of the driveforce of the mover, the vibration of the stator is prevented and thestage unit is capable of high accurate positioning while moving a sampleplaced on itself.

In the first stage unit of the present invention, if the reactioncanceling mechanism can apply to any arbitrary point of the stator aforce having an arbitrary magnitude and an arbitrary direction, thereaction canceling mechanism may generate one kind of force and apply itto an appropriate point (for example, applying a force having the samemagnitude as the reaction and opposite direction to the point ofreaction application of the stator) to cancel a reaction caused bydriving the mover translationally. However, when the stator isrotationally driven or the point of the stator to which the reactioncanceling mechanism applies the force is fixed, it is generallyimpossible to cancel the reaction just by giving the stator one kind offorce.

Therefore, in the first stage unit of the present invention, it ispreferred for the reaction canceling mechanism to generate a force toact on at least two points of the stator and cancel the reaction as awhole. In this case, if the reaction canceling mechanism can applyforces having an arbitrary magnitude and an arbitrary direction to atleast two fixed points of the stator, the reaction acting on the statorby a translational driving, a rotational driving or the combination ofthe both can be canceled. Especially, when the reaction acting on thestator is a force along a predetermined plane, the reaction can becanceled by applying two kinds of forces being along the predeterminedplane and having magnitude and direction corresponding to the reaction.

The aforementioned case shows a case where the reaction cancelingmechanism can apply the force having an arbitrary magnitude and anarbitrary direction to the stator. However, in a case where the pointsof the stator to which the reaction canceling mechanism applies theforces are fixed and the direction of the force applied to each point ispredetermined, the reaction generally can not be canceled just byapplying two kinds of forces to the stator. In such a case, the reactioncanceling mechanism generates forces having respective predetermineddirections, which cancel the reaction as a whole, and applies them to atleast three points of the stator, thereby being able to cancel thereaction acting on the stator by a translational driving, a rotationaldriving or the combination of the both. Especially, if the reactionacting on the stator is a force along a predetermined plane, thereaction can be canceled by the reaction canceling mechanism applyingthree kinds of forces having magnitudes corresponding to the reactionand predetermined directions not parallel to each other, which areapplied on three fixed points of the stator and are along thepredetermined plane.

In the first stage unit of the present invention, the driving unit canbe so structured that the drive force of the mover is generated byelectromagnetic interaction. In such a case, as described above, thereaction acting on the stator on driving the mover can be accuratelyidentified before driving the mover by generating the drive force forthe mover by using electromagnetic interaction excellent incontrollability and linearity. Therefore, the reaction acting on thestator can be canceled with high response-speed and accuracy by thereaction canceling mechanism applying a force to cancel the reactionacting on the stator to the stator in a manner like feed-forwardsimultaneously with driving the mover. That is, the stator appears to befree from the reaction.

The driving unit which generates the drive force for the mover byelectromagnetic interaction is so structured that, for example, thestator has an armature unit including a plurality of armature coils,which are arranged in the shape of a matrix in a predetermined plane andhave current paths almost parallel to the predetermined plane, and themover has a driving magnetic pole unit to generate a magnetic fluxhaving a direction crossing the predetermined plane.

In the first stage unit of the present invention equipped with thisdriving unit, the reaction canceling mechanism is so structured thatreaction canceling magnetic pole units to generate a magnetic fluxhaving a direction crossing the current paths of armature coils disposedon four corners of the armature unit and a control system that controlsthe direction and amplitude of currents supplied for the armature coilsdisposed on four corners of the armature unit are equipped. In thiscase, by the control system controlling the direction and amplitude ofcurrents supplied for the armature coils disposed on four corners of thearmature unit and the electromagnetic interaction between magnetic fieldinduced by the magnetic pole units and the currents flowing in thearmature coils disposed on four corners of the armature unit, the forcecanceling the reaction is applied to the stator along the samepredetermined plane as the plane that the reaction is along.Accordingly, four forces along a predetermined plane, which haverespective predetermined directions in the four fixed points of thestator and have magnitudes corresponding to the reaction, are appliedwith good controllability and the reaction can be canceled veryaccurately.

Incidentally, when applying to the stator the force to cancel thereaction acting on the stator on driving the mover, the reactioneventually comes to act on the reaction canceling magnetic pole units.It is preferred that the reaction canceling magnetic pole units and thestator are mechanically independent from each other to prevent thevibration from transmitting to the stator by the reaction acting on thereaction canceling magnetic pole units.

The reaction canceling magnetic pole units can be structured so thatforces perpendicular to each other in neighboring corners of thearmature unit are generated. In such a case, the force to cancel thereaction acting on the stator can be easily calculated.

From a second aspect, the present invention is a method of making astage unit comprising a process to provide a driving unit including themover and the stator; and a process to provide the reaction cancelingmechanism to apply the force canceling the reaction, which is induced bythe driving of the mover and is acting on the stator, to the stator bythe electromagnetic interaction. According to this, by providing thedriving unit and the reaction canceling mechanism and combining theseand other elements mechanically, electrically, and optically as the needarises, the first stage unit of the present invention is made.

From a third aspect, the present invention comprises the armature unitincluding a plurality of armature coils, which are arranged in the shapeof a matrix on the predetermined plane and whose current paths arealmost parallel to the predetermined plane; the magnetic pole unithaving a plurality of magnets magnetized in directions not perpendicularto the predetermined plane and two-dimensionally generating analternating magnetic field with a period of 4P/3 in two axis-directionsperpendicular to each other practically without generating any magneticfield in an area opposite to the armature unit; and a current drivingunit to move the magnetic pole unit relatively to the armature unit in aplane parallel to the predetermined plane by supplying currents to thearmature coils respectively. Hereinafter, this stage unit is referred toas a “second stage unit of the present invention”.

According to this, in making a steady magnetic circuit having a lowmagnetic resistance, the magnetic pole unit is composed only of theaforementioned magnets without using other magnetic members than themagnets, thereby realizing the light weight of the mover. Accordingly,the driving force of the mover can be reduced and the reaction acting onthe stator can be reduced, thereby the vibration of the stator can bedecreased and highly accurate positioning can be realized while moving aplaced sample at a high speed.

The second stage unit of the present invention can further comprise amagnetic member supporting the armature coils in a side opposite to themagnetic pole unit. In such a case, a magnetic circuit is structuredthrough the magnetic pole unit and the magnetic member, thereby a steadymagnetic circuit having a low magnetic resistance can be structured.Therefore, a magnetic flux having high flux density can be generated inthe positions of the armature coils. Incidentally, as a material for themagnetic member, one having high electric resistance, high saturationmagnetic flux density, low magnetic hysteresis, and low coercive forceis preferred.

Also, the second stage unit of the present invention can furthercomprise a flat-plate-like shaped member disposed between the armatureunit and the magnetic pole unit and made of a non-magnetic andnon-conductive material. In such a case, when structuring the magneticpole unit so that it is not contacting the armature unit by anair-bearing system, an air blown out of the magnetic pole unit is blownon the flat-plate-like shaped member, thereby the magnetic pole unit andthe flat-plate-like shaped member, eventually the armature unit can benon-contacting each other. Furthermore, because the flat-plate-likeshaped is non-magnetic and non-conductive, the magnetic flux generatedby the magnetic pole unit is not affected. Accordingly, an easyimplementation of relative movement at high speed by a small drivingforce is possible. Incidentally, a non-magnetic material means amaterial having magnetic permeability small enough compared with amagnetic material such as iron, etc. and almost equal to that of theair. Furthermore, a non-conductive material means a material havingconductance small enough compared with a conductive material such ascopper, etc. and almost equal to that of the air.

Furthermore, the second stage unit of the present invention can be sostructured that the current driving unit supplies currents for therespective armature coils independently. In such a case, the value anddirection of each of currents supplied for the respective armature coilscan be controlled independently, thereby the magnetic pole unit and thearmature unit can be relatively moved in a predetermined direction.

Furthermore, the second stage unit of the present invention comprises aposition detection system to detect the positional relation between themagnetic pole unit and the armature unit; and a control unit(controller) to control at least one of the value and direction of eachof currents supplied for the respective armature coils via the currentdriving unit based on detection results by a position detection. In sucha case, the relative position and the relative speed between themagnetic pole unit and the armature unit can be controlled bycontrolling the value and direction of the respective currents flowingin the armature coils based on position information (speed information)obtained by the position detection system with respect to the magneticpole unit and the armature unit.

The second stage unit comprising the position detection system and thecontrol unit described above is so structured that the control unitselectively supplies currents for the armature coils opposite with themagnetic pole unit. In such a case, with not supplying currents forarmature coils in which no or just weak Lorentz force is induced,efficient current supply is possible and current dissipation can bereduced while maintaining the driving force.

From a fourth aspect, the present invention is a making methodcomprising a process to provide the armature unit including a pluralityof armature coils having a current path almost parallel to thepredetermined plane and being arranged in the shape of a matrix on thepredetermined plane; a process providing the magnetic pole unit having aplurality of magnets magnetized in directions not perpendicular to thepredetermined plane and two-dimensionally generating an alternatingmagnetic field with a period of 4P/3 in two axis-directionsperpendicular to each other practically without generating any magneticfield in an area opposite to the armature unit; and a process providinga current driving unit to move the magnetic pole unit relatively to thearmature unit in a plane parallel to the predetermined plane bysupplying currents for the armature coils respectively. According tothis, by providing the armature unit, the magnetic pole unit and thedriving unit, and then combining and adjusting these and other elementsmechanically, electrically, and optically as the need arises, the secondstage unit of the present invention is made.

In this case, furthermore, it is possible to include a process toprovide the position detection system to detect a positional relationbetween the magnetic pole unit and the armature unit; and a process toprovide the control unit to control at least one of the value anddirection of each of currents supplied for the respective armature coilsthrough the current driving unit based on detection results by aposition detection. In such a case, a stage unit, in which the relativeposition and the relative speed between the magnetic pole unit and thearmature unit can be controlled, can be made.

Incidentally, needless to say, both the first stage unit and the secondstage unit can be applied to one stage unit. In such a case, thereaction can be accurately canceled as well as reducing the reactionacting on the stator by, for example, decreasing the driving force ofthe magnetic pole unit as a mover.

Furthermore, by applying both the making method of the first stage unitand that of the second stage unit to the making of one stage unit, astage unit to which both the first stage unit and the second stage unitare applied can be made.

From a fifth aspect, out of exposure apparatuses that expose thesubstrate by irradiating an energy beam and transfer a predeterminedpattern onto the substrate, the present invention is an exposureapparatus having a feature of comprising a stage unit as a positioncontrol unit to control the position of the substrate.

According to this, by exposing the substrate placed on the stage unit ofthe present invention, a move at a high speed and highly accuratecontrol of position of the substrate are possible, and both thethrough-put and the accuracy of exposure can be improved.

From a sixth aspect, out of making methods of an exposure apparatus thatexposes a substrate by irradiating an energy beam and transfers anpredetermined pattern onto the substrate, the present invention is amethod of making the stage unit by providing the driving unit includingthe mover and the stator, and the reaction canceling mechanism to applythe force canceling the reaction, which is induced by the driving of themover and is acting on the stator, to the stator by the electromagneticinteraction; and an exposure apparatus making method including thedisposing of the stage unit as a position control apparatus to controlthe position of the substrate. According to this, an exposure unitcomprising the first stage unit of the present invention as a positioncontrol apparatus to control the position of the substrate is made.

From a seventh aspect, out of making methods of an exposure apparatusthat exposes a substrate by irradiating an energy beam and transfers anpredetermined pattern onto the substrate, the present invention is amethod of making the stage unit by providing the armature unit includinga plurality of armature coils that are arranged in the shape of a matrixon the predetermined plane and have current paths almost parallel to thepredetermined plane, the magnetic pole unit having a plurality ofmagnets magnetized in directions not perpendicular to the predeterminedplane and two-dimensionally generating an alternating magnetic fieldwith a period of 4P/3 in two axis-directions perpendicular to eachother, between the armature coils and itself, practically withoutgenerating any magnetic field in an area opposite to the armature unit,and the current driving unit to move the magnetic pole unit relativelyto the armature unit in a plane parallel to the predetermined plane bysupplying currents for the armature coils respectively; and an exposureapparatus making method including the disposing of the stage unit as aposition control apparatus to control the position of the substrate.According to this, an exposure unit comprising the second stage unit ofthe present invention as a position control apparatus to control theposition of the substrate is made.

Incidentally, needless to say, an exposure apparatus can be structuredwhich comprises a stage unit, to which both the first stage unit and thesecond stage unit of the present invention are applied, as a positioncontrol apparatus to control the position of the substrate. In such acase, both the through-put and the accuracy of exposure can be improved.

Furthermore, by applying both the making method of an exposure apparatuscomprising the first stage unit and the making method of an exposureapparatus comprising the second stage unit of the present invention tothe making of one exposure apparatus, an exposure apparatus can be madewhich comprises a stage unit to which both the first stage unit and thesecond stage unit of the present invention are applied.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the schematic arrangement of an exposureapparatus according to an embodiment of the present invention;

FIG. 2 is a perspective diagram showing an arrangement around the stageunit of the exposure apparatus of FIG. 1;

FIG. 3 is a diagram showing the arrangement of the magnetic pole unit;

FIGS. 4(A) to 4(H) are diagrams (No.1) showing the arrangements ofpermanent magnet modules composing the magnetic pole unit and the shapesof permanent magnets;

FIGS. 5(A) to 5(D) are diagrams (No.2) showing the arrangements ofpermanent magnet modules composing the magnetic pole unit and the shapesof permanent magnets;

FIGS. 6(A) to 6(C) are diagrams illustrating the arrangement of magneticpoles in the magnetic pole unit;

FIG. 7 is a diagram showing an arrangement around the stator;

FIGS. 8(A) and 8(B) are diagrams showing the arrangement of aflat-plate-like shaped coil module;

FIGS. 9(A) and 9(B) are diagrams showing the arrangement of a reactioncanceling magnetic pole unit;

FIG. 10 is a diagram illustrating the principle of the scanning-exposureof the exposure apparatus of FIG. 1;

FIGS. 11(A) and 11(B) are diagrams illustrating magnetic circuits withrespect to the magnetic pole unit;

FIGS. 12(A) and 12(B) are diagrams illustrating forces acting onarmature coils upon the drive of the mover;

FIGS. 13(A) to 13(C) are diagrams illustrating a magnetic flux densityaround an armature coil, a supply current to the armature coil, and aforce acting on an armature coil upon the drive of the mover;

FIGS. 14(A) and 14(B) are diagrams illustrating a magnetic circuit withrespect to a reaction canceling magnetic pole unit;

FIGS. 15(A) and 15(B) are diagrams illustrating forces acting on anarmature coil upon the canceling of the reaction;

FIG. 16 is a diagram illustrating the action of reaction canceling;

FIG. 17 is a diagram illustrating a variation of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below withreference to FIG. 1 to FIG. 16. FIG. 1 shows the entire configuration ofan exposure apparatus. 100 according to the embodiment of the presentinvention. Incidentally, this exposure apparatus 100 is an exposureapparatus based on the so-called step and scan exposure method.

The exposure apparatus 100 comprises: an illumination system 10; areticle stage RST holding a reticle R as a mask; a projection opticalsystem PL; a stage unit 30 to drive a wafer W as a substrate in X-Ytwo-dimensional directions on an X-Y plane (including rotational movesaround Z axis ; and a control system for controlling these elements.

The illumination system 10 is comprised of a light source, anilluminance uniformization optical system constituted by a fly-eye lensand the like, a relay lens, a variable ND filter, a reticle blind, adichroic mirror, and the like (none of which are shown). The arrangementof such an illumination system is disclosed in, for example, JapanesePatent Laid-Open No. 10-112433. This illumination system 10 illuminatesa slit-like (in the shape of rectangle or circular arc) illuminationarea portion IRA (refer to FIG. 10) defined by the reticle blind abovethe reticle R, on which a circuit pattern and the like are drawn, withillumination light IL and with almost uniform illuminance.

The reticle R is fixed on the reticle stage RST by, for example, vacuumchucking. In order to position the reticle R, the reticle stage RST canbe finely driven within the X-Y plane perpendicular to the optical axisof the illumination system 10 (which coincides with an optical axis AXof the projection optical system PL (to be described later)) by areticle stage driving unit (not shown) formed by a magnetic levitationtype two-dimensional linear actuator, and can also be driven in apredetermined scanning direction (the Y direction in this case) at adesignated scanning velocity. In this embodiment, the above magneticlevitation type two-dimensional linear actuator includes a Z drive coilin addition to X and Y drive coils, and hence can finely drive thereticle stage RST in the Z direction as well.

The stator of the two-dimensional linear actuator described above issupported by a reaction frame (not shown) disposed independently from asupporting member 40. Therefore, the reaction acting on the stator ofthe two-dimensional linear actuator is transmitted through the reactionframe to the ground (floor) but not to the supporting member 40 ondriving the reticle stage RST. Such transmission through a reactionframe to the ground is disclosed in, for example, the U.S. patentapplication Ser. No. 08/416,558. The disclosure in the United StatesPatent Application described above is fully incorporated by referenceherein as long as the national laws in designated states or electedstates, to which this international application is applied, permit.

The position of the reticle stage RST within a stage moving plane isdetected all the time through a movable mirror 15 by a reticleinterferometer 16 fixed on the supporting member 40 as a positiondetection unit with a resolution of, for example, 0.5 to 1 nm.Positional information of the reticle stage RST from the reticleinterferometer 16 is sent to a stage control system 19 and the stagecontrol system 19 drives the reticle stage RST via a reticle stagedriving portion (not shown) based on the positional information of thereticle stage RST. Incidentally, in practice, a movable mirror having areflection surface perpendicular to the scanning direction (Y axisdirection) and a movable mirror having a reflection surfaceperpendicular to the non-scanning direction (X axis direction) areattached on the reticle stage RST and the reticle interferometer 16 hasone axis in the scanning direction and two axes in non-scanningdirection. In FIG. 1; however, the movable mirror 15 and the reticleinterferometer 16 are representatively shown.

The projection optical system PL is arranged under the reticle stage STas shown in FIG. 1, and the optical axis AX (coinciding with the opticalaxis IX of the illumination optical system) is set as the Z-axisdirection. In this embodiment, a refraction optical system is employedwhich is structured of a plurality of lenses disposed along the opticalaxis AX at a predetermined interval, so as to make a double telecentricoptical arrangement. The projection optical system PL is a reductionoptical system having a predetermined magnification of, for example, ⅕(or ¼). Therefore, when the illuminating light emitted by theillumination system 10 illuminates the illumination area IAR of thereticle R, a reduced image (a partially inverted image) of a circuitpattern of the reticle R is formed on an exposure area IA on a wafer W,which is conjugate with the illumination area IRA (refer to FIG. 10).The image is formed on the wafer W, which has a photoresist coated onits surface, through the projection optical system PL by theillumination light that passes through the reticle R.

The stage unit 30 comprises: a base 21; a substrate table 18 supportedby air levitation with an air slider (to be described later) above theupper surface of this base 21 via a clearance of several microns or so;and a driving unit 50 for driving the substrate table 18 within the X-Yplane in two-dimensional directions.

A wafer holder 25 is fixed on the substrate table 18 and a wafer W isheld by the wafer holder 25 using, for example, vacuum chucking.

Furthermore, a movable mirror 27 to reflect a laser beam from a waferlaser interferometer (referred to as “wafer interferometer” hereafter)31, which is fixed on the supporting member 40 as a position detectionunit, is fixed on the substrate table 18. The position of the wafer W inX-Y plane is detected all the time by the externally placedwafer-interferometer 31 with a resolution of 0.5 to 1 nm or so. As shownin FIG. 1, the wafer-interferometer 31 is attached on the supportingmember 40. Positional information (or speed information) of the wafer issent to the stage control system 19 and then to the main control unit20, and the stage control system 19 controls the driving unit 50 via thecurrent driving unit 22 in accordance with instructions from the maincontrol unit 20 and based on the Positional information (or speedinformation). Incidentally, in practice as shown in FIG. 2, a movablemirror 27Y having a reflection surface perpendicular to the scanningdirection (Y axis direction) and a movable mirror 27X having areflection surface perpendicular to the non-scanning direction (X axisdirection) are attached on the substrate table 18 and the waferinterferometer 31 has one axis in the scanning direction and two axes inthe non-scanning direction. In FIG. 1, however, the movable mirror 27and the wafer interferometer 31 are representatively shown.

The reticle stage RST (excluding the not shown stator) described above,the projection optical system, the base 21, the reticle interferometer16, and the wafer interferometer 31 are held by the supporting member 40and mechanically combined.

Furthermore, the exposure apparatus of the present embodiment 100comprises reaction canceling magnetic pole units 45X, 45Y to generate amagnetic field for applying a force canceling a reaction acting on thestator 60 of the driving unit 50 to the stator 60. Incidentally, thereaction canceling magnetic pole unit 45X generates a magnetic field tocancel X-component of the reaction acting on the stator 60 and thereaction canceling magnetic pole unit 45Y generates a magnetic field tocancel Y-component of the reaction acting on the stator 60. Thestructure of the reaction canceling magnetic pole units 45X, 45Y will bedescribed later. Incidentally, in practice, as shown in FIG. 2, thereaction canceling magnetic pole units 45X1, 45X2 are disposed in therespective corners of two corners in a first diagonal relation out ofthe four corners of the stator. In FIG. 1, however, just the reactioncanceling magnetic pole units 45X is illustrated representing these. Andthe reaction canceling magnetic pole units 45Y1, 45Y2 are disposed inthe respective corners of two corners in a second diagonal relation outof the four corners of the stator. In FIG. 1, however, just the reactioncanceling magnetic pole units 45Y is illustrated representing these.

On the substrate table 18, a fiducial mark plate (not shown) is fixed onwhich various kinds of fiducial marks for the measurement of base linesto measure the distance between the detection center of analignment-detection system (not shown) of the off-axis method and theoptical axis of the projection optical system PL are formed.

Furthermore, the exposure apparatus 100, shown in FIG. 1, comprises amultiple focal position detection system which is one of focus detectingsystems (or focal point detecting systems) based on the obliqueincidence method. The system is for detecting the position in Zdirection (the direction of optical axis AX) of the area including theexposure area IA on the wafer W's surface and the neighborhood. Thismultiple focal position detection system comprises an illuminationoptical system (not shown) and a light receiving system (not shown). Thedetailed configuration of the multiple focal position detection systemis disclosed in, for example, Japanese Patent Laid-Open No. 6-283403 andits corresponding U.S. Pat. No. 5,448,332. The disclosure of thismultiple focal position detection system in the United States Patentdescribed above is fully incorporated by reference herein as long as thenational laws in designated states or elected states, to which thisinternational application is applied, permit.

As the driving unit 50, a planar motor-composed of the stator 60embedded in the upper portion of the base 21 and a mover 51 fixed to thebottom portion (the surface side opposite with the base) of thesubstrate table 18, is used. In the following description, the drivingunit 50 will be referred to as the planar motor 50 for the sake ofconvenience. The detailed description of the structure of this planarmotor 50 and the structure of the reaction canceling mechanism to cancelthe reaction acting on the stator will follow.

The mover 51 is, in the present embodiment, so structured that permanentmagnet modules (52N, 52S, 53N, 53S, 54N, 54S) and permanent magnets 55,56, as shown in FIG. 3, are arranged in a shape of mesh as a whole in aplanar view. In the following description, this mover is also referredto as a driving magnetic pole unit 51 for the sake of convenience.Furthermore, the permanent magnet modules 52N, 53N, 54N are magnetshaving the surface opposite with the stator 60 practically magnetized asN pole, and the permanent magnet modules 52S, 53S, 54S are magnetshaving the surface opposite to the stator 60 practically magnetized as Spole. Incidentally, in FIG. 3, hollow portions are surrounded by thicklines and to show the numbers of the components except for the left endand the right end of the mesh-like structure, those numbers are writtenon the respective components omitting leader lines.

In the driving magnetic pole unit 51, the permanent magnet modules 52N,52S are arranged alternately in the shape of a matrix in the center ofthe mesh-like structure described above. Furthermore, the permanentmagnet modules 53N, 53S are arranged alternately on the four corners ofthe mesh-like structure and the permanent magnet modules 54N, 54S arearranged alternately on each end, and between the permanent magnetmodule 52N and the permanent magnet module 52S, between the permanentmagnet module 52N and the permanent magnet module 54S, and between thepermanent magnet module 52S and the permanent magnet module 54N, apermanent magnet 55 is placed respectively, and between the permanentmagnet module 53N and the permanent magnet module 54S, between thepermanent magnet module 53S and the permanent magnet module 54N, andbetween the permanent magnet module 54N and the permanent magnet module54S, a permanent magnet 56 is placed respectively.

Incidentally, as shown in FIG. 3, it is when an odd number of thepermanent magnet modules 52N, 52S are placed both in the lateraldirection (X axis direction) and longitudinal direction (Y axisdirection) that the permanent magnet modules 53N, 53S are alternatelyarranged on the four corners of the mesh-like structure. When an evennumber of the permanent magnet modules 52N, 52S are placed in thelateral direction, the permanent magnet modules 53N's or 53S's areplaced on the both of the two corners in the lateral direction, and whenan even number of the permanent magnet modules 52N, 52S are placed inthe longitudinal direction, the permanent magnet modules 53N's or 53S'sare placed on the both of the two corners in the longitudinal direction.Accordingly, when an even number of the permanent magnet modules 52N,52S are placed both in the lateral direction and the longitudinaldirection, the permanent magnet modules 53N's or 53S's are placed on theall four corners of the mesh-like structure.

Furthermore, in the present embodiment, the permanent magnet modules52N, 52S are arranged in the shape of a square matrix.

The permanent magnet module 52N, as shown in FIG. 4(A), has a squarebottom surface with P/3 as the length of one side, takes H as the heightof the periphery and has such a shape that a concave is formed in thecenter of the upper surface as a whole. This permanent magnet module 52Ncomprises four of permanent magnet 57N having the shape of a wedge shownin FIG. 4(B). Such a permanent magnet 57N has a surface becoming theperiphery of the permanent magnet module 52N to be S pole and anothersurface becoming the center of the permanent magnet module 52N to be Npole when assembled.

The permanent magnet module 52S is, as shown in FIG. 4(C), in the sameshape as the permanent magnet module 52N. This permanent magnet module52S comprises four of permanent magnet 57S having the shape of a wedgeshown in FIG. 4(D). Such a permanent magnet 57S has a surface becomingthe periphery of the permanent magnet module 52S to be N pole andanother surface becoming the center of the permanent magnet module 52Sto be S pole when assembled.

The permanent magnet module 53N, as shown in FIG. 4(E), has a squarebottom surface with P/6 as the length of one side, takes H as theheight, and has such a shape that the permanent magnet module 52N isdivided into four equal parts by two planes respectively parallel to twoside-surfaces of the permanent magnet module 52N, which areperpendicular to each other. This permanent magnet module 53N comprisestwo of permanent magnet 58N having the shape of a wedge shown in FIG.4(F). Such a permanent magnet 58N has such a shape that the permanentmagnet 57N is divided into two equal parts by a plane perpendicular toits bottom surface and S pole surface.

The permanent magnet module 53S, as shown in FIG. 4(G), has a squarebottom surface with P/6 as the length of one side, takes H as theheight, and has such a shape that the permanent magnet module 52S isdivided into four equal parts by two planes respectively parallel to twoside-surfaces of the permanent magnet module 52S. This permanent magnetmodule 53S comprises two of permanent magnet 58S having the shape of awedge shown in FIG. 4(H). Such a permanent magnet 58S has such a shapethat the permanent magnet 57S is divided into two equal parts by a planeperpendicular to its bottom surface and N pole surface.

The permanent magnet module 54N, as shown in FIG. 5(A), has arectangular bottom surface with P/3 as the length of its long side andwith P/6 as the length of its short side, takes H as the height, and hassuch a shape that the permanent magnet module 52N is divided into twoequal parts by a plane parallel to its side-surface. This permanentmagnet module 54N comprises one permanent magnet 57N and two permanentmagnets 58N's. Furthermore, the permanent magnet module 54S, as shown inFIG. 5(B), has a rectangular bottom surface with P/3 as the length ofits long side and with P/6 as the length of its short side, takes H asthe height and has such a shape that the permanent magnet module 52S isdivided into two equal parts by a plane parallel to its side-surface.This permanent magnet module 54S comprises one permanent magnet 57S andtwo permanent magnets 58S's.

The permanent magnet 55, as shown in FIG. 5(C), is in the shape of arectangular solid having a square bottom surface with P/3 as the lengthof one side and taking H as the height, and has two side-surfaces as apair opposite with each other, of which one is N-pole surface and theother is S-pole surface. Furthermore, the permanent magnet 56, as shownin FIG. 5(D), is in the shape of a rectangular solid having arectangular bottom surface with P/3 as the length of one side and P/6 asthe length of the other side and taking H as the height, and has twoside-surfaces as a pair opposite, in the long-arm direction, with eachother of which one is N-pole surface and the other is S-pole surface.

The magnetic pole unit 51 is so structured that the bottom surfaces ofthe permanent magnet modules (52N, 52S, 53N, 53S, 54N, 54S) and thepermanent magnets 55, 56 are arranged in one plane to form thearrangement shown in FIG. 3 in a planar view. Incidentally, thepermanent magnets 55, 56 are so disposed that their magnetic-polesurfaces have polarity opposite from the respective magnetic-polesurfaces of the permanent magnet modules 52N, 52S, 53N, 53S, 54N, 54S,which are opposite with those surfaces.

As described above, the driving magnetic pole unit 51 is structured bycombining the permanent magnets magnetized in other directions than Zaxis and no yoke material is used. Therefore, the driving magnetic poleunit 51 as a mover is lightweight.

The arrangement of the polarity of the respective permanent magnets inthe driving magnetic pole unit 51 composed according to the abovedescription is shown in FIG. 6. FIG. 6(A) shows a planar view of thearrangement of the polarity of the respective permanent magnets in thedriving magnetic pole unit 51, FIG. 6(B) shows the arrangement of thepolarity of the respective permanent magnets which is seen by looking atthe driving magnetic pole unit 51 in FIG. 6(A) from the below, and FIG.6(C) shows the arrangement of the polarity of the respective permanentmagnets in the A—A cross section of FIG. 6(A). Incidentally, FIG. 6(B)and FIG. 6(C) show the arrangement in X-axis direction of the polarityof the respective permanent magnets, meanwhile the same arrangement istrue in Y-axis direction as well.

The driving magnetic pole unit 51 has an air slider, not shown,(aero-hydrostatic bearing) fastened on itself, and has the substratetable 18 attached in its upper surface via a supporting mechanism (notshown). In the air slider, a pressured air supplied via a connected airtube from a air pump (not shown) is blew towards the upper surface ofthe base 21, and the substrate table 18 with the magnetic pole unit 51is levitated and supported by a static pressure (so-called pressureinside the gap) of the air layer between the upper surface of the base21 and the driving magnetic pole unit 51.

As shown in FIG. 7, partially-broken-out section including thesupporting unit 40, the base 21 including the stator 60 comprises arectangular-shaped container 69, in a planar view, which is shaped likea two-stepped concave and is open in the upper side; a flat-plate-likeshaped magnetic member 62 made of a material such as ferrite stainlessor carbon steel, fastened to the step portion in the bottom of thiscontainer 69 from the above, and attached in the center portion of theheight; and a flat-plate-like shaped member 68 made of a non-magneticand non-conductive material such as ceramic or the like, and attached sothat the upper side of the container 69 is closed.

On the upper side surface of the magnetic member 62, a plurality ofarmature coils 63's are disposed. As an armature unit, theflat-plate-like shaped coil module 61 is composed of these plurality ofarmature coils 63's, and the stator 60 of the planar motor 50 iscomposed of the flat-plate-like shaped coil module 61 and the magneticmember 62. The arrangement of armature coils 63's composing theflat-plate-like shaped coil module 61 is described later.

Incidentally, to prevent the temperature increase of the armature coils63's and other members near them and the fluctuation of the ambientatmosphere of the armature coils 63's, which is due to heat-generationcaused by current supply to the armature coils 63's, cooling of thearmature coils 63's is performed. Such cooling is realized by making aclosed space surrounded by the flat-plate-like shaped member 68, thecontainer 69, and the magnetic member 62 to be a path for a coolant tocool the armature coils 63's of the flat-plate-like shaped coil module61. Therefore, an inlet opening (not shown) is set on one side of theclosed space and an outlet opening (not shown) is set on another side ofthe close space. A coolant (for example, water or FLUORINERT (productname of Sumitomo-3M Corp.) is sent into the closed space through theinlet opening from a cooling control mechanism (not shown) andheat-exchange with the flat-plate-like shaped coil module 61 isperformed upon passing the inside of the closed space, thereby thecoolant heated up by the absorption of the heat generated in theflat-plate-like shaped coil module 61 is sent out of the outlet opening.

The flat-plate-like shaped coil module 61 is composed of a plurality ofthe armature coils 63's arranged in the shape of a matrix as shown inFIG. 8(A), planar view, along with the reaction canceling magnetic poleunit 45X1, 45X2, 45Y1, 45Y2. This armature coil 63 is, as shown in FIG.8(B), in the shape of a rectangular solid having an almost-square bottomsurface with P as the length of one side (parallel to X-Y plane) andhaving a hole in Z direction around the center axis CX parallel toZ-axis. The cross section of the hole has the shape of a square with P/3as the length of one side. The current driving unit 22 supplies acurrent via terminals 64 a and 64 b for the armature coil 63 and thecurrent flows in almost uniform current density including its insidearound the center axis CX. Incidentally, the value and direction ofcurrent flowing the armature coil 63 is controlled via the currentdriving unit 22 by the stage control system 19 and this control isexecuted for each armature coil 63. Furthermore, in FIG. 8(A), thearmature coils 63's have the same structure and armature coils on thefour corner opposite with the reaction canceling magnetic pole unit45X1, 45X2, 45Y1, 45Y2 are particularly shown as armature coils 63C1,63C2, 63C3, 63C4.

The reaction canceling magnetic pole unit 45X1 is, as shown in FIG.9(A), composed of a supporting member 46, a flat-plate-like shapedmagnetic member 47 made of a material such as ferrite stainless orcarbon steel, and two permanent magnets 48N, 48S. Incidentally, FIG.9(A) is drawn upside down for the convenience.

The supporting member 46, as shown in FIG. 9(A), FIG. 2, and FIG. 8(A),comprises a L-letter-like shaped flat plate portion almost parallel tothe flat-plate-like shaped member 68, which is placed on theflat-plate-like shaped member 68; a first column expanding verticallyand downwards from one end of the L-letter-like shaped flat plateportion; a second column expanding vertically and downwards from theother end of the L-letter-like shaped flat plate portion; a first fixingportion set in the bottom end of the first column; and a second fixingportion set in the bottom end of the second column. And the supportingmember 46 is fixed on a floor independently from the supporting member40 in the first and second fixing portions. Therefore, the reactioncanceling magnetic pole unit 45X1 is mechanically independent from othermembers composing the exposure apparatus 100.

Referring back to FIG. 9(A), the flat-plate-like shaped magnetic member47 has the shape of a square with P as the length of one side in aplanar view and is fixed by screws, adhesive, etc. in the edge of theL-letter-like shaped flat plate portion of the supporting member 46,which is on the surface opposite with the flat-plate-like shaped member68.

The permanent magnets 48N, 48S have the shape of a square with P/3 asthe length of one side in a planar view, are arranged along X-axisdirection in the surface of the flat-plate-like shaped magnetic member47 opposite with the flat-plate-like shaped member 68, and are fixed byscrews, adhesive, or the like. In the permanent magnet 48N, the surfaceopposite with the flat-plate-like shaped member 68 is N pole, and in thepermanent magnet 48S, the surface opposite with the flat-plate-likeshaped member 68 is S pole. These permanent magnets 48N, 48S are, asshown in FIG. 9(B), disposed opposite with each other around the centerof armature coil 63C1's current path, that is, the winding with respectto Y-axis direction.

The reaction canceling magnetic pole unit 45X2 has the same structure asthe reaction canceling magnetic pole unit 45X1, and the reactioncanceling magnetic pole unit 45Y1, 45Y2 are composed in the same manneras the reaction canceling magnetic pole unit 45X1 except for permanentmagnets 48N, 48S being arranged in Y-axis direction.

In the exposure apparatus 100 according to the present embodiment, asshown in FIG. 10, the reticle R is illuminated in a rectangular (orslit-like) illumination area IAR of which the longitudinal direction isperpendicular to the scanning direction (Y-axis direction) of thereticle R. The reticle R is scanned at a speed V_(R) in the (−Y)direction upon exposure. The illumination area IAR (the center of whichalmost coincides with the optical axis AX) is projected onto the wafer Wvia the projection optical system PL. A slit-shaped projection area,which is conjugate with the illumination area IAR, that is, the exposurearea IA, is formed. The wafer W and the reticle R have an inverted imageforming relationship. The wafer W is, thus scanned at a velocity V_(W)synchronously with the reticle R in the direction opposite to thescanning direction of the reticle R, allowing the entire shot area SA onthe wafer W to be exposed. The velocity ratio V_(W)/V_(R) of thescanning speed precisely corresponds to the reduction ratio of theprojection optical system PL, and the pattern of the pattern area PA ofthe reticle R is accurately reduced and transferred onto the shot areaSA on the wafer W. The width in the longitudinal direction of theillumination area IAR is determined so as to be wider than that of thepattern area PA on the reticle R and to be narrower than the maximumwidth of the area including the shielding area ST. And by scanning thereticle R, the entire pattern area PA is illuminated.

Hereinafter, the operation of each part of the embodiment during thetime when the wafer W is moving will be described. Firstly, the movementof the wafer W in this embodiment, that is, the outline of the principleof driving of the driving magnetic pole unit 51, as a mover, of theplanar motor 50, will be described by referring to FIGS. 11 to 13.

In the driving magnetic pole unit 51, as shown by solid arrows in FIG.11(A) representatively illustrating the case concerning the permanentmagnet modules 52N, 52S, the permanent magnet modules 52N, 53N, 54Ngenerate magnetic fluxes in the (−Z) direction (downwards in the figure)and the permanent magnet modules 52S, 53S, 54S generate magnetic fluxesin the (+Z) direction (upwards in the figure). And these permanentmagnet modules compose a magnetic circuit together with the permanentmagnets 55, 56, and the magnetic member 62. Incidentally, in composingthe magnetic circuit, the magnetic member 62 is used in all magneticcircuits, the permanent magnet 55 is used in a magnetic circuitconcerning the permanent magnet modules 52N and 52S, and the permanentmagnet 56 is used in a magnetic circuit concerning the permanent magnetmodules 54N and 54S. Furthermore, the permanent magnet 55 is used in amagnetic circuit concerning the permanent magnet modules 52N and 54S (or52S and 54N), and the permanent magnet 56 is used in a magnetic circuitconcerning the permanent magnet modules 53N and 54S (or 53S and 54N).

In the following, a magnetic circuit concerning the permanent magnets52N, 52S will be described as an example.

In a magnetic circuit shown in FIG. 11(A), a magnetic flux density Baround the magnetic member 62, that is, in Z position where theflat-plate-like shaped coil module 61 is placed, takes a distributionshown in FIG. 11(B). That is, the absolute value of the magnetic fluxdensity B is maximum in positions corresponding to the center points ofthe permanent magnet modules 52N, 52S, decreases as going from thecenter points to the periphery of the permanent magnet modules 52N, 52Srespectively, and takes zero at the middle between the positioncorresponding to the center point of the permanent magnet module 52N andthe position corresponding to the center point of the permanent magnetmodule 52S. Furthermore, the distribution of the magnetic flux density Bis symmetric in (±)X direction with the positions corresponding to thecenter points of the permanent magnet modules 52N, 52S as centers. Thatis, the X-directional distribution of the magnetic flux density B issuch that it can be approximated by a sine function or trapezoidalfunction. Incidentally, in FIG. 11(B), when the direction of themagnetic flux is (+Z) direction, the value of the magnetic flux densityB takes positive, and when the direction of the magnetic flux is (−Z)direction, the value of the magnetic flux density B takes negative.Furthermore, the same distribution as the X-directional distribution ofthe magnetic flux density B that FIG. 11(B) shows is true in Y directionas well.

Incidentally, in the present embodiment, as a material for magneticmembers, for example, ferrite stainless, carbon steel, or the like whichis of high resistance, high saturation magnetic flux density, lowmagnetic hysteresis, and low coercive force is used, thereby it ispossible to decrease eddy currents, hysteresis losses, and magneticresistance and successively generate a magnetic flux of high magneticflux density even when the driving magnetic pole unit 51 is moving.

In the following, the driving of the mover 51 by Lorentz force generatedby an interaction between a magnetic flux, between the driving magneticpole unit 51 and the magnetic member 62, and a current flowing thearmature coil 63 will be described.

Under the environment of the magnetic flux density B having thedistribution shown in FIG. 11(B), when a current is supplied to thearmature coil 63, a Lorentz force is generated in the armature coil 63.The magnitude and direction of the Lorentz force vary depending on apositional relation between the driving magnetic pole unit 51 and theflat-plate-like shaped coil module 61. Assume that, firstly, thepositional relation between the driving magnetic pole unit 51 and theflat-plate-like shaped coil module 61 is a positional relation, shown inFIG. 12(A), among armature coils 63, 63 ₂, 63 ₃, 63 ₄, . . . , permanentmagnets 52N₁, 52N₂, . . . , and permanent magnets 52S₁, 52S₂, . . . toconsider the Lorentz force. Incidentally, in FIG. 12(A), the armaturecoils 63, 63 ₂, 63 ₃, 63 ₄ are drawn by solid lines and the permanentmagnets 52N₁, 52N₂, 52S₁, 52S₂ are drawn by dashed lines.

That is, assume that the armature coils 63 ₁, 63 ₂, 63 ₃, 63 ₄ aresequentially arranged in X direction and the permanent magnets 52N₁,52N₂, 52S₁, 52S₂ are sequentially arranged along X0-axis parallel to Xdirection. Furthermore, assume that, in FIG. 12(A), the left edge of thearmature coil 63 ₁ and the left edge of the permanent magnets 52N₁ areapart from each other by a distance ΔX.

In such a arrangement-relation, pay attention to points Q1, Q2, Q3, Q4in the armature coils 63 ₁, 63 ₂, 63 ₃, 63 ₄, shown in FIG. 12(B), whichare along X1-axis parallel to the X0-axis. Furthermore, assume that, asillustrated in FIG. 12(A), the X0-axis and the X1-axis are apart fromeach other by a distance δY in Y direction, the point Q1 and the pointQ2 are apart from each other by a distance P in X direction, and thepoint Q3 and the point Q4 are apart from each other by a distance P in Xdirection.

When the driving magnetic pole unit 51 has moved in X direction, thatis, the distance ΔX changes, a magnetic flux density B₁ (ΔX; δY) in thepoint Q1 changes in a way shown by a solid line in FIG. 13(A). Such achange is the same as in FIG. 11. Now, assuming the distribution in theFIG. 11 to be well approximated by a sine function, the magnetic fluxdensity B₁ (ΔX; δY) is given by

B ₁ (ΔX; δY)=B ₀(δY)×sin {(3π/2P)ΔX+φ}  (1).

The value φ is a constant determined by X position of the point Q1, B₀(δY) is a constant determined according to δY.

Furthermore, when the driving magnetic pole unit 51 has moved in Xdirection, that is, the distance ΔX changes, a magnetic flux density B₂(ΔX; δY) in the point Q2 changes in a way shown by a dashed line in FIG.13(A). Now, assuming the distribution to be well approximated by a sinefunction, the magnetic flux density B₂ (ΔX; δY) is given by

B ₂(ΔX; δY)=−B ₀(δY)×cos {(3π/2P)ΔX+φ}  (2).

B₂ (ΔX; δY) is obtained by shifting B₁ (ΔX; δY) in X direction by ¼ ofthe period.

When supplying a current I₁ (ΔX; δY) shown by a solid line in FIG. 13(B)and given by

I ₁(ΔX)=I ₀ sin{(3π/2P)ΔX+φ}  (3)

for the armature coil 63 ₁, and supplying a current I₂ (ΔX; δY) shown bya dashed line and given by

I ₂(ΔX)=−I ₀ cos{(3π/2P)ΔX+φ}  (3)

for the armature coil 63 ₂, assuming that I₁ (ΔX) flows only in Y-axisdirection in the point Q1 and I₂ (ΔX) flows only in Y-axis direction inthe point Q2, the X-component FX1 (ΔX; δY) of Lorentz force per aunit-length generated in the point Q1 shown in FIG. 12(B) is given by

FX1(ΔX; δY)=B ₁(ΔX; δY)×I ₁(ΔX)  (5),

and the X-component FX2 (ΔX; δY) of Lorentz force per a unit-lengthgenerated in the point Q2 shown in FIG. 12(B) is given by

FX2(ΔX; δY)=B ₂(ΔX; δY)×I ₂ (ΔX)  (6).

Then, the resultant force, F (δY), of FX1 (ΔX; δY) and FX2 (ΔX; δY) isgiven by

F(δY)=B ₀(δY)×I ₀  (7).

That is, also when the driving magnetic pole unit 51 moves, theresultant force from the X-component of Lorentz force per a unit-lengthin the point Q1 and the X-component of Lorentz force in the point Q2 isconstant independently of the X-position of the driving magnetic poleunit 51, that is, the distance ΔX as shown in FIG. 13(C).

In the above description, it was assumed that all currents flow inY-axis direction in the points Q1 and Q2. However, currents in thepoints Q1 and Q2 can have a X-component. In such a case, consideringthat the directions of currents in the points Q1 and Q2 are parallel toeach other due to the periodicity of the arrangement of the armaturecoils 63's, by supplying currents different from each other in phase by¼ of the period to the armature coils 63 ₁, 63 ₂, the X-component of theresultant force from the Lorentz force per a unit-length in the point Q1and the Lorentz force in the point Q2 is constant independently of theX-position of the driving magnetic pole unit 51.

Furthermore, the selection of the point Q1 in the armature coil 63 ₁ isarbitrary and the point Q2 corresponding to the point Q1 is uniquelydetermined in the armature coil 63 ₂ by all means. Accordingly, bycontrolling the current I₁ (ΔX) supplied to the armature coil 63 ₁ andthe current I₂ (ΔX) supplied to the armature coil 63 ₂ to respectivelysatisfy the equations (3) and (4), the X-component of the resultantforce from the Lorentz force generated in the armature coil 63 ₁ and theLorentz force in the armature coil 63 ₂, can be constant independentlyof the X-position of the driving magnetic pole unit 51. Incidentally,the magnitude of X-component of the resultant force can be controlled bychanging the value I₀ in the equations (3) and (4).

When exchanging the points Q1, Q2 with the points Q3, Q4, it is easy tounderstand that also when applying the same current-control as thearmature coils 63 ₁, 63 ₂ to the armature coils 63 ₃, 63 ₄, theX-component of the resultant force of the Lorentz forces can becontrolled to be constant independently of the X-position of the drivingmagnetic pole unit 51 in the same manner as in the armature coils 63 ₁,63 ₂. Incidentally, the amount of X-component of the resultant force canbe controlled by changing the value I₀ in the equations (3) and (4).Furthermore, when applying the same current-control as the armaturecoils 63 ₁, 63 ₂ to any two armature coils 63's adjacent to each other,the X-component of the resultant force of the Lorentz forces can becontrolled to be constant independently of the X-position of the drivingmagnetic pole unit 51.

Therefore, by selecting a pair of two armature coils adjacent to eachother in X direction according to the X-position of the driving magneticpole unit 51 and controlling the currents of each pair of the armaturecoils 63's to satisfy the equations (3) and (4), the driving magneticpole unit 51 can be driven in X direction by a arbitrary and constantdriving force independently of the X-position of the driving magneticpole unit 51.

Incidentally, considering a pair of the armature coils 63's, whensupplying currents to drive the driving magnetic pole unit 51 in Xdirection, generally a force to drive the driving magnetic pole unit 51in Y direction and a torque around Z-axis are generated. Therefore, thecurrent of each armature coil 63 is so adjusted that a force to drivethe driving magnetic pole unit 51 in Y direction and a torque becomezero as a whole.

Furthermore, in the above, a case where X-directional distribution of amagnetic flux density B around the flat-plate-like shaped coil module 61is well approximated by a sine function is described, however, if suchan approximation is not appropriate, instead of the equations (3) and(4), the currents I₁ (ΔX), I₂ (ΔX) supplied to the armature coils 63 ₁,63 ₂ can be determined by using the following equations:

I ₁(ΔX)=C ₀ sin²{(3π/2P)ΔX+φ}/B ₁(ΔX; δY)  (8)

I ₂(ΔX)=C ₀ cos²{(3π/2P)ΔX+φ}/B ₂(ΔX; δY)  (9).

C₀ is a constant.

Using these equations, the resultant force, F (δY), of FX1 (ΔX; δY) andFX2 (ΔX; δY) is given by

F(δY)=C ₀ (δY)  (10).

That is, also when the driving magnetic pole unit 51, the X-component ofthe resultant force from the Lorentz force generated in the point Q1 andthe Lorentz force in the point Q2 can be constant.

In the above case where-the driving magnetic pole unit 51 moves in Xdirection, the X-directional drive of the driving magnetic pole unit 51is described. Also about the Y-directional drive of the driving magneticpole unit 51, the driving magnetic pole unit 51 can be driven by aconstant driving force in Y direction independently of the Y-position ofthe driving magnetic pole unit 51 in the same manner as in X direction.That is, by adaptively selecting a pair of two armature coils 63'sadjacent to each other in Y direction and controlling currents accordingto similar equations to the equations (3) and (4), or the equations (8)and (9), besides, by controlling currents so that the driving force todrive the driving magnetic pole unit 51 in X direction becomes zero andthe torque of the driving magnetic pole unit 51 is cancelled as a whole,the driving magnetic pole unit 51 can be driven by a constant drivingforce in Y direction independently of the Y-position of the drivingmagnetic pole unit 51.

Furthermore, by supplying a current having a pattern, which is obtainedby superposing a current-pattern of X-directional drive on acurrent-pattern of Y-directional drive with an appropriate rate, to eacharmature coil 63, the driving magnetic pole unit 51 can be driven in anydirection on X-Y plane by a driving force having an arbitrary magnitude.

Furthermore, by driving the driving magnetic pole unit 51 withoutcanceling the torque, the driving magnetic pole unit 51 can berotationally driven in a desired direction by a desired torque.

Therefore, according to the planar motor 50 of the present embodiment,making use of the advantages of the Lorentz force method that isexcellent in controllability, linearity of thrust, and positioningaccuracy, the light-weight driving magnetic pole unit 51 can be drivenin any direction on X-Y plane by a driving force having an arbitrarymagnitude.

In the stage unit 30 of the present embodiment, as described above, thesubstrate table 18 that holds a wafer W via the wafer holder 25 isattached to the driving magnetic pole unit 51. Thus, by controlling thedrive of the driving magnetic pole unit 51 via the stage controller 19as described above, the main controller 20 can move the substrate table18 and the wafer W integrally with the driving magnetic pole unit 51freely on the X-Y plane. More specifically, when the driving magneticpole unit, that is, the substrate table 18 is moved in a desireddirection by using a desired thrust, the main controller 20 monitors themeasurement values of the wafer interferometer 31 (positionalinformation or the velocity information) via the stage control system19, and obtains the relative-position relationship between the mover 51and the stator within the X-Y plane. And the main controller 20calculates and determines the value and direction of a current to besupplied to each armature coil 63 in accordance with the obtainedrelative-position information and the target position to which thesubstrate table 18 is to be driven, and then the main controller 20sends instructions to the stage control system 19. Consequently, thestage control system 19 controls the value and direction of the electriccurrent to be supplied to each armature coil 63 via the current drivingunit 22 (not shown). In this case, the main controller 20 also controlsthe speed of the substrate table 18 in accordance with the distance tothe target position.

The main controller 20 may calculate the value and direction of thecurrent to be supplied to each armature coil 63, at each time-point ofmove, according to the positional information (or velocity information)sent by the wafer interferometer 31. However, if its control responsetime is not short enough, the main controller 20 may calculate the valueand direction of the current to be supplied to each armature coil 63correspondingly to the passage of time, that is, the move of the mover51 at the start of the move so that the wafer W takes a desired locusand speed in a certain subsequent time-period. In this case, the maincontroller 20 calculates the deviation of the wafer W from the desiredlocus based on the positional information (or velocity information) sentfrom the wafer interferometer 31, corrects the value and direction ofthe current to be supplied to each armature coil 63, and calculates thevalue and direction of the current for a predetermined time-periodsubsequent to the correction in time series. Then, the stage system 19controls the current of each armature coil 63 according to the correctedinformation.

In the present embodiment, in the drive of the driving magnetic poleunit 51, the stage control system 19 detects the armature coil 63opposite with the driving magnetic pole unit 51 according to thepositional information (or velocity information) sent from the waferinterferometer 31 and controls the current driving unit 22 so that thecurrent to drive the driving magnetic pole unit 51 is supplied only tothat armature coil 63. Therefore, because the current is not supplied toan armature coil 63 to generate no or weak Lorentz force, the currentconsumption can be efficiently reduced maintaining the driving force.

Next, concerning the present embodiment, an outline about the principleof canceling of the reaction acting on the stator 60 will be describedreferring to FIG. 14 to FIG. 16.

In the reaction canceling magnetic pole unit 45X1, as shown by solidarrows in FIG. 14(A), the permanent magnet 48N generates a magnetic fluxin (−Z) direction (downwards in the FIG. ), and the permanent magnet 48Sgenerates a magnetic flux in (+Z) direction (upwards in the FIG. ). Anda magnetic circuit in which the magnetic flux flows sequentially in thepermanent magnet 48N, the magnetic member 62, the permanent magnet 48S,and the magnetic member 47 is formed.

In this case, around the-upper surface of the magnetic member 62, thatis, Z position where a armature coil 63C1 being one of the armaturecoils 63's constituting the flat-plate-like shaped coil module 61 isplaced, the magnetic flux density B takes a distribution shown in FIG.14(B). That is, the absolute value of the magnetic flux density B ismaximum at positions corresponding to the centers of the permanentmagnets 48N, 48S, and as going out from the positions to positionscorresponding to the peripheries of the permanent magnets, the absolutevalue of the magnetic flux density B decreases. Then at the middlebetween the position corresponding to the center of the permanentmagnets 48N and the position corresponding to the center of thepermanent magnets 48S, the absolute value of the magnetic flux density Btakes zero. Furthermore, the distribution of the magnetic flux density Bis point-symmetric with the positions corresponding to the center pointsof the permanent magnet modules 48N, 48S as centers. Incidentally, inFIG. 14(B), the value of the magnetic flux density B is positive whenthe direction of the magnetic flux is (+Z) direction and the value ofthe magnetic flux density B is negative when the direction of themagnetic flux is (−Z) direction.

Moreover, at Z position where a armature coil 63C1 is placed, thereaction canceling magnetic pole unit 45X1 generates the same magneticflux density B as in FIG. 14(B).

Furthermore, at Z positions where armature coils 63C2, 63C4 are placed,the reaction canceling magnetic pole units 45Y1, 45Y2 generate amagnetic flux density B of which the distribution has the X-direction inFIG. 14(B) changed to Y-direction.

Under the environment of a magnetic flux density B having thedistribution shown in FIG. 14(B), when a left-handed current IX1, in aplanar view, shown in FIG. 15(A) is supplied to the armature coil 63C1,by an electro-magnetic interaction, a Lorentz force FCX1 ₁ is generatedin (+X) direction in an opposite portion of the armature coil 63C1 withthe permanent magnet 48N and a Lorentz force FCX1 ₂ is generated in (+X)direction in an opposite portion of the armature coil 63C1 with thepermanent magnet 48S. Consequently, the resultant force of the Lorentzforce FCX1 ₁ and FCX1 ₂ acts on the armature coil 63C1 in (+X)direction, and is applied to the stator. In this way, the force FCX1 canbe generated along the same plane as a plane along which the reactionacting on the stator 60 due to the drive of the magnetic pole unit 51,that is, the Lorentz force generated in the armature coil 63 is.Incidentally, the magnitude of the force FCX1 is proportional to thecurrent IX1.

Moreover, when a right-handed current IX1, in a planar view, shown inFIG. 15(B) is supplied to the armature coil 63C1, by an electromagneticinteraction, a Lorentz force FCX1 ₁ is generated in (−X) direction in anopposite portion of the armature coil 63C1 with the permanent magnet 48Nand a Lorentz force FCX1 ₂ is generated in (−X) direction in an oppositeportion of the armature coil 63C1 with the permanent magnet 48S.Consequently, the resultant force of the Lorentz force FCX1 ₁ and FCX1 ₂acts on the armature coil 63C1 in (−X) direction, and is applied to thestator.

That is, by controlling the direction and magnitude of the currentsupplied to the armature coil 63C1, the force FCX1 of a desiredmagnitude in a desired direction, (+X) or (−X) direction, is applied tothe placement-position of the armature coil 63C1 of the stator 60.

Moreover, also in the armature coil 63C3, in the same manner as thearmature coil 63C1, by controlling the direction and magnitude of thecurrent supplied to the armature coil 63C3, the force FCX2 of a desiredmagnitude in a desired direction, (+X) or (−X) direction, is applied tothe placement-position of the armature coil 63C3 of the stator 60 (referto FIG. 16).

Furthermore, also in the armature coil 63C2, 63C4, in the same manner asthe armature coil 63C1, by controlling the directions and magnitudes ofthe current supplied to the armature coils 63C2, 63C4, the forces FCY1,FCY2 of a desired magnitude in a desired direction, (+X) or (−X)direction, are applied to the respective placement-positions of thearmature coils 63C2, 63C4 of the stator 60 (refer to FIG. 16).

Incidentally, as shown in FIG. 16, when the driving magnetic pole unit51 is driven by a force F, a reaction (−F) acts on point R of thestator. Now, represent the X-component of the reaction (−F) by (−FX),the Y-component of the reaction (−F) by (−FY), and the distance betweena line along which the reaction (−F) is and the gravity center G of thestator 60 by D.

To cancel such a reaction, representing the X-components of the forcesFCX1, FCX2 by CX1, CX2, the Y-components of the forces FCY1, FCY2 byCY1, CY2, and the magnitude of the reaction by F, then, forces FCX1,FCX2, FCY1, FCY2 given by the following equations should be applied:$\begin{matrix}{{FX} = {{CX1} + {CX2}}} & (11) \\{{FY} = {{CY1} + {CY2}}} & (12) \\{{F \cdot D} = {{{CX1} \cdot {LY1}} - {{CX2} \cdot {LY2}} + {{CY1} \cdot {LX1}} - {{CY2} \cdot {{LX2}.}}}} & (13)\end{matrix}$

Incidentally, the Y-directional distances between the gravity center Gand the respective points where the forces FCX1, FCX2 are applied arerepresented by LY1, LY2 and the X-directional distances between thegravity center G and the respective points where the forces FCY1, FCY2are applied are represented by LX1, LX2.

In the above equations (11) to (13), because the number of unknownvariables (CX1, CX2, CY1, CY2) is four and the number of the equationsis three, a solution can be found. By choosing a group of FCX1, FCX2,FCY1, FCY2 satisfying the equations (11) to (13) and supplying currentsto generate them to the armature coils 63C1, 63C2, 63C3, 63C4, thereaction acting on the stator 60 due to the drive of the drivingmagnetic pole unit 51 can be cancelled. Incidentally, the exposureapparatus 100 of the present embodiment chooses one that makes the totalamount of supply-currents smaller out of groups of FCX1, FCX2, FCY1,FCY2 satisfying the equations (11) to (13).

In the exposure apparatus 100 of the present embodiment, the maincontrol unit 20, via the stage control system 19 and the current drivingunit 22, drives the driving magnetic pole unit 51 by supplying thecurrent to the armature coil 63 opposite with the driving magnetic poleunit 51 as described above, and simultaneously cancels the reaction thatis known to itself and acts on the stator 60 by applying the forcesFCX1, FCX2, FCY1, FCY2 that are generated by the electromagneticinteraction and satisfy the equations (11) to (13). Accordingly, becausethe force to accurately cancel the reaction is applied to the stator 60with no delay-time from the act of the reaction, the reaction acting onthe stator 60 due to the drive of the driving magnetic pole unit 51 canbe very accurately cancelled.

Incidentally, in the above, the cancellation of the reaction in thetranslational drive is described. In the case of a rotational drive, twokinds of reactions act on the stator 60. In this case, the entirereaction can be cancelled by calculating forces to cancel the respectivereactions and applying the resultant force of those forces to thestator.

Moreover, the reaction canceling magnetic pole units 45X1, 45X2 45Y1,45Y2 are fixed on a floor, etc. via the respective supporting members46's independently of the stator and the other elements of the exposureapparatus 100. Therefore, although, when applying the forces FCX1, FCX2,FCY1, FCY2 to the stator 60 to cancel the reaction acting on the statordue to the drive of the driving magnetic pole unit 51, reactions againstthose forces come to act on the reaction canceling magnetic pole units45X1, 45X2 45Y1, 45Y2, the reactions do not cause the vibration of thestator 60, the supporting member 40, and the like. Therefore, positionalinformation (or the velocity information) detected by the reticleinterferometer 16 fixed on the supporting member and the waferinterferometer 31 does not include the effect of the drive of thedriving magnetic pole unit 51.

Next, the brief description of the flow of a exposure operation in theexposure apparatus 100 including the aforementioned stage unit will bepresented.

First, a reticle R, on which a pattern to be transferred is formed, isloaded onto the reticle stage RST by a reticle loader. Similarly, awafer W to be exposed is loaded onto the substrate table 18 by a waferloader.

At this point, the substrate table 18 is supported by air levitation ata predetermined wafer loading position on the base 21. The maincontroller 20 servo-controls the substrate table 18 via the stage system19 based on the measurement value of the wafer interferometer, so thatthe substrate table 18 stays positioned at the loading position for apredetermined period of time. When the substrate table 18 is staying atthe loading position, the electric current is supplied to each armaturecoil 63 of the stator 60 of the planar motor 50. Accordingly, the maincontroller 20 cools each armature coil 63 via a cooling device, etc. soas to prevent the temperature of the armature coil 63 from rising due tothe generated heat.

Next the main controller 20 prepares for a reticle alignment and a baseline measurement in a predetermined procedure, by using what is called areticle microscope (not shown), a reference mark plate (not shown inFigures) mounted on the substrate table 18, and an alignment detectingsystem (not shown). And by using the alignment detection system,alignment measurement such as EGA (Enhanced Global Alignment) of whichthe details are disclosed in the Japan Patent Laid Open No. 61-44429 andthe corresponding U.S. Pat. No. 4,780,617 is performed. During suchoperations, when the wafer W needs to be moved, the main controller 20controls the current supplied to the each armature coil 63 within thestage unit via the stage control system 19 and moves the mover 51 so asto move the wafer W. Simultaneously with the drive of the drivingmagnetic pole unit 51, the main controller 20 controls the currents ofthe armature coils 63C1, 63C2, 63C3, 63C4 in the stage unit via thestage control system, and cancels the reaction acting on the stator 60due to the drive of the driving magnetic pole unit 51. After completingsuch alignment measurement, a step-and-scan exposure is performed, inthe following manner. The disclosures, cited above are fullyincorporated by reference herein as long as the national laws indesignated states or elected states, to which this internationalapplication is applied, permit.

Upon exposure, first of all, the substrate table 18 is moved so that theX-Y position of the wafer W is positioned at a scanning startingposition of the first shot area (first shot). This movement is performedby the main controller 20 controlling the current supplied to eacharmature coil 63 (including the armature coils 63C1, 63C2, 63C3, 63C4)constituting the planar motor 50 via the stage control system 19, asdescribed above. Simultaneously, the reticle stage RST is moved so thatthe X-Y position of the reticle is at a scanning starting position. Thismovement is performed by the main controller 20 via the stage controlsystem 19 and the reticle driving portion (not shown).

Then, the stage control system 19 synchronously moves the reticle R andthe wafer W via the reticle driving portion (not shown) and the planarmotor 50 while canceling the reaction acting on the stator 60. This isperformed in accordance with the X-Y positional information of thereticle R measured by the reticle interferometer 16, and the X-Ypositional information of the wafer W, which is measured by the waferinterferometer 31. With this synchronized movement of the reticle andthe wafer, scanning exposure is performed.

When the transfer of a reticle pattern onto a shot area by scanningexposure controlled as described above is completed, the substrate table18 is stepped by a distance of one shot area. Then, scanning exposure isperformed on the next shot area. Also in this stepping, the reactionacting on the stator 60 is cancelled according to the X-Y positionalinformation of the wafer W, which is measured by the waferinterferometer 31 while moving the wafer W by the planar motor 50.

The stepping operation and scanning exposure are repeatedly performed insequence, thus, transferring the necessary number of patterns onto thewafer W. Therefore, with the exposure apparatus 100 according to thisembodiment, by using the stage unit having the planar motor 50, thepositioning of the wafer W can be achieved with high accuracy at a highspeed. As a consequence, the exposure with high exposure precision canbe achieved, improving the throughput. That is, by having the exposureapparatus 100 of the present embodiment comprise the planar motor 50 andother elements such as the illumination system 10, the projectionoptical system PL, etc. shown in FIG. 1, the exposure apparatus withhigh exposure precision and improved throughput can be realized.

Incidentally, according to this embodiment, the permanent magnets aredisposed in the mover (driving magnetic pole unit) and the reactioncanceling magnetic pole unit, and the armature coils are disposed in thestator, however, it is possible that the armature coils are disposed inthe mover (driving magnetic pole unit) and the reaction cancelingmagnetic pole unit, and the permanent magnets are disposed in thestator.

Moreover, according to this embodiment, the mover is levitated from thestator by the air guide mechanism. However, also an electromagneticlevitation mechanism can be used. Moreover, electromagnets equivalent topermanent magnets can be used instead of the permanent magnets.

Furthermore, according to this embodiment, on each of the four cornersof the stator, the reaction canceling magnetic pole units are placed,however, even if those are placed on three of the four corners, thereaction can be canceled. Moreover, even if, on any three or morepoints, the reaction canceling magnetic pole units to generate forcesthat are not in the same direction are placed, the reaction can becanceled.

Furthermore, in this embodiment, a liquid coolant is used for coolingthe armature coils. However, as long as it is a fluid that can serve asa coolant, a gas coolant may be used.

Additionally, the number of the driving magnetic pole units 51's as amover arranged on the stator is not limited to 1. For instance, asillustrated in FIG. 17, two driving magnetic pole units 51's may bearranged on a stator 60, then the two driving magnetic pole units can bedriven independently so that the exposure of a wafer can be performed byusing one driving magnetic pole unit 51, whereas having the otherdriving magnetic pole unit 51 to perform the delivery, etc. of thewafer. In such a case, although two or more kinds of reactions act onthe stator, the reactions can be canceled by calculating forces tocancel the respective reactions and applying the resultant force of themto the stator similarly with the embodiment described above.

Moreover, the stage unit 30 according to the embodiment is applicable tothe reticle stage RST. In this case, the aforementioned reaction framecan be omitted.

The exposure apparatus 100 according to the embodiment can be made byhaving the reticle stage RST comprising plenty of mechanical elements,the projection optical system PL comprising a plurality of lenses, andthe base 21 mounted on the supporting member 40, having other elements,such as the stage unit 30 and the reaction canceling magnetic pole unit45X, 45Y, than the base 21 attached to the base 21, and having acomprehensive adjustment (electric adjustment, function confirmation,etc.) performed. Also, the base 21 may be attached independently of thesupporting member 40.

Incidentally, it is preferred that the making of the exposure apparatus100 is performed in a clean room where the temperature, the degree ofcleanness, etc. are controlled.

Furthermore, the present invention can be applied to all of waferexposure apparatuses, liquid crystal exposure apparatuses, etc. such asa reduced projection exposure apparatus using ultraviolet light as itslight source, a reduced projection exposure apparatus using a soft X-rayof which the wavelength is 10 nm or so as its light source, a reducedprojection exposure apparatus using X-rays of 1 nm or so in wavelengthas its light source, an exposure apparatus using EB (Electron Beams) orion beams. Furthermore, the present invention may be applied to astep-and-repeat type apparatus, a step-and-scan type apparatus, and astep-and-stitch type apparatus. However, in the case when this inventionis applied to a reduced projection exposure apparatus using a soft X-rayof which the wavelength is 10 nm or so as its light source, a reducedprojection exposure apparatus using X-rays of 1 nm or so in wavelengthas its light source, an exposure apparatus using EB (Electron Beams) orion beams, where the surrounding environment of the wafer and the likeneed to be in vacuum, it is necessary to employ the magnetic levitationmechanism because the air guide mechanism can not be used as thelevitation mechanism to levitate the mover from the stator.

Industrial Applicability

As described above, the stage unit according to the present inventionapplies the force to cancel the reaction acting on the stator due to thedrive of the mover to the stator by the electromagnetic interaction andthe mover is made light weight by composing the magnetic pole unit, thatcomposes the mover, by combining magnets having suchmagnetization-directions that their magnetic flux are toward the statorand magnets having magnetization-directions crossing the aforementionedmagnetization-directions without using yoke material, thereby thevibration of the stator can be prevented even upon the high speed driveof the mover. Therefore, the stage unit is suitable for performing thehighly precise positioning control while moving a placed sample.

Furthermore, the exposure apparatus according to the present inventioncontrols the position of the wafer, etc. accurately and at a high speed,therefore the exposure apparatus is suitable for highly accurateexposure.

What is claimed is:
 1. A stage unit having a movable stage comprising: adriver that includes a mover and a stator to drive the movable stage;and a reaction canceling mechanism that applies to the stator a force tocancel a reaction acting on the stator due to driving of the mover by anelectromagnetic interaction at least a part of the reaction cancelingmechanism being disposed above the stator.
 2. The stage unit accordingto claim 1, wherein the reaction canceling mechanism generates forces,which cancel the reaction as a whole, in at least two points of thestator.
 3. The stage unit according to claim 2, wherein the reactionacting on the stator and the forces generated in at least two points arealong a plane.
 4. The stage unit according to claim 2, wherein thereaction canceling mechanism generates forces, which cancel the reactionas a whole and have respective predetermined directions, in at leastthree points of the stator.
 5. The stage unit according to claim 1,wherein the driver generates a driving force of the mover by anelectromagnetic interaction.
 6. The stage unit according to claim 5,wherein the stator comprises an armature unit including a plurality ofarmature coils that are arranged in the shape of a matrix and havecurrent paths almost parallel to the predetermined plane, and the movercomprises a driving magnetic pole unit that generates a magnetic fluxhaving a direction that cross the predetermined plane.
 7. The stage unitaccording to claim 6, wherein the reaction mechanism comprises reactioncanceling magnetic pole units that generate magnetic fluxes crossing thecurrent paths of armature coils arranged on the four corners of thearmature unit; and a control system that controls the directions andamplitudes of currents supplied to the armature coils arranged on thefour corners of the armature unit.
 8. The stage unit according to claim7, wherein the reaction canceling magnetic pole units and the stator aremechanically independent of each other.
 9. The stage unit according toclaim 7, wherein the reaction canceling magnetic pole units generateforces perpendicular to one another on the neighboring corners of thearmature unit.
 10. An exposure apparatus that transfers a predeterminedpattern onto a wafer by irradiating an energy beam and exposing thewafer, comprising: a stage unit according to claim 1 as the positioncontroller to control the position of the wafer.
 11. The making methodof a stage unit having a movable stage comprising the steps of:providing a driver including a mover and a stator to drive the movablestage; and providing the reaction canceling mechanism that applies aforce to cancel the reaction acting on the stator due to driving of themover to the stator by an electromagnetic interaction, at least a partof the reaction canceling mechanisms being disposed above the stator.12. A stage unit comprising: an armature unit that includes a pluralityof armature coils, which are arranged in the shape of a matrix and havecurrent paths almost parallel to the predetermined plane; a magneticpole unit that has a plurality of magnets magnetized in directions notperpendicular to the predetermined plane and two-dimensionally generatesan alternating magnetic field with a period of 4P/3 in twoaxis-directions perpendicular to each other, between the armature coilsand itself, practically without generating any magnetic field in an areaopposite to the armature unit P of the 4P/3 being a coil module width;and a current driver that moves the magnetic pole unit relatively to thearmature unit in a plane parallel to the predetermined plane bysupplying currents to the respective armature coils.
 13. The stage unitaccording to claim 12 further comprising: a magnetic member supportingthe armature coil in a side opposite with the magnetic pole unit. 14.The stage unit according to claim 12 further comprising: aflat-plate-like shaped member that is placed between the armature unitand the magnetic pole unit and made of a non-magnetic material.
 15. Thestage unit according to claim 12, wherein the current driver suppliescurrents to the respective armature coils independently.
 16. The stageunit according to claim 12 further comprising: a position detectionsystem that detects the positional relation between the magnetic and thearmature unit; and a controller that controls at least one of the valueand direction of currents supplied to the respective armature coils viathe current driver according to the detection results of the positiondetection system.
 17. The stage unit according to claim 16, wherein thecontrol selectively supplies currents only to the armature coilsopposite with the magnetic pole unit.
 18. An exposure apparatus thattransfers a predetermined pattern onto a wafer by irradiating an energybeam and exposing the wafer, comprising: a stage unit according to claim12 as the position controller to control the position of the wafer. 19.The making method of a stage unit comprising the steps of: providing anarmature unit that includes a plurality of armature coils, which arearranged in the shape of a matrix and have current paths almost parallelto the predetermined plane; providing a magnetic pole unit that has aplurality of magnets magnetized in directions not perpendicular to thepredetermined plane and two-dimensionally generates an alternatingmagnetic field with a period of 4P/3 in two axis-directionsperpendicular to each other, between the armature coils and itself,practically without generating any magnetic field in an area opposite tothe armature unit, P of the 4P/3 being a coil module width; andproviding a current driver that moves the magnetic pole unit relativelyto the armature unit in a plane parallel to the predetermined plane bysupplying currents to the respective armature coils.
 20. The makingmethod of a stage unit according to claim 19 further comprising thesteps of: providing a position detection system that detects thepositional relation between the magnetic and the armature unit; andproviding a controller that controls at least one of the value anddirection of currents supplied to the respective armature coils via thecurrent driver according to the detection results of the positiondetection system.
 21. The making method of an exposure apparatus thattransfers a predetermined pattern onto a wafer by irradiating an energybeam and exposing the wafer, comprising the steps of: making a stageunit by providing an armature unit including a plurality of armaturecoils that are arranged in the shape of a matrix and have current pathsalmost parallel to the predetermined plane; a magnetic pole unit thathas a plurality of magnets magnetized in directions not perpendicular tothe predetermined plane and two-dimensionally generates an alternatingmagnetic field with a period of 4P/3 in two axis-directionsperpendicular to each other, between the armature coils and itself,practically without generating any magnetic field in an area opposite tothe armature unit; and a current driver that moves the magnetic poleunit relatively to the armature unit in a plane parallel to thepredetermined plane, P of the 4P/3 being a coil module width; andplacing the stage unit as the position controller that controls theposition of the wafer.
 22. An exposure apparatus that transfers apattern onto a first wafer by irradiating an energy beam and exposingthe first wafer, comprising: a first wafer stage that holds the firstwafer; a driver having a stator and a mover coupled to the first waferstage to drive the first wafer stage; and a reaction canceling systemthat applies to the stator an electromagnetic force to cancel a reactionforce acting on the stator due to driving of the mover, at least a partof the reaction canceling system being disposed above the stator. 23.The exposure apparatus according to claim 22, wherein the driver is aplanar motor.
 24. The exposure apparatus according to claim 22, furthercomprising: a second wafer stage that holds a second wafer.
 25. Theexposure apparatus according to claim 22, wherein the mover comprises amagnet member.
 26. The exposure apparatus according to claim 22, whereinthe mover comprises a magnet member without a yoke member.
 27. Anexposure apparatus that transfers a pattern onto a first wafer byirradiating an energy beam and exposing the first wafer, comprising: afirst wafer stage that holds the first wafer; a driver having a statorand a mover coupled to the first wafer stage to drive the first waferstage; and a reaction canceling system that applies to the stator anelectromagnetic force to cancel a reaction force acting on the statordue to driving of the mover, the reaction canceling system cooperatingwith the stator to generate the electromagnetic force.
 28. The exposureapparatus according to claim 27, wherein the driver is a planar motor.29. The exposure apparatus according to claim 27, further comprising asecond wafer stage that holds a second wafer.
 30. The exposure apparatusaccording to claim 27, wherein the mover comprises a magnet member. 31.The exposure apparatus according to claim 27, wherein the movercomprises a magnet member without a yoke member.